Pivot axle assembly for roadworthy railroad ballast tamper apparatus

ABSTRACT

A rail tamper apparatus is provided, including a chassis configured for being hitched to a semi-tractor trailer for road travel, and also configured for travel on rails of a railroad track, at least one ballast tamping unit mounted to the chassis, a turntable unit mounted to the chassis, and a pivoting axle assembly mounted to the chassis that is retractable relative to the chassis in a road travel position for highway travel, and is extendable from the chassis into a track travel position for operation on the rails, and including a rail wheel drive motor being extendable with the axle assembly.

RELATED APLICATION

This application claims 35 USC 119(e) priority from U.S. ProvisionalPatent application No. 61/882,192 filed Sep. 25, 2013.

BACKGROUND

The present disclosure relates generally to a ballast tamper machine formanipulating track ballast under railroad ties and correcting alignmentof railroad tracks. More particularly, the present disclosure relates toa railroad right of way maintenance system providing a ballast tampingmachine being transportable on a highway and easily convertible betweenroad travel and rail travel and including a retractable pivoting railwheel axle assembly.

Due to natural factors, such as floods, hurricanes, tornados, orseasonal ground shifting, as well as regular rail maintenance schedules,it is often necessary to correct the vertical and/or horizontalalignment of railroad tracks by manipulating the track ballastsupporting railroad ties using a method known as tamping. Conventionaltamping machines include vibrating elongate, rigid tamping arms, alsoreferred to as tamping tools. The tamping tools are forced into theballast on each side of the railroad tie, and vibrate at a givenfrequency within the ballast. Such vibration, in addition to movement ofthe tamper tool work head, causes movement of the ballast to support theties, and the corresponding track at a designated alignment, therebyleveling the railroad tracks.

However, conventional tamper machines are very heavy, long, and overlybulky for highway transportation. Further, even if the tamper machinecan be transportable using, for example, a large trailer, specialoversize permits and requirements are required by the U.S. Department ofTransportation for carrying the tamper machine on a highway. Moreover,once the machine reaches its destination, a heavy-duty lifting machinesuch as a crane, is needed to move the tramper onto the railway trackfor operation. Accordingly, the transportation of conventional tampermachines is inconvenient and cumbersome, and incurs high shipping costsdue to the difficulties in transporting.

SUMMARY

A roadworthy tamper apparatus or machine is provided, which features achassis having at least one tamper workhead, at least one turntableunit, at least one reference projector buggy, and at least one set ofretractable rail wheels, all mounted to the chassis that is towable as atrailer by a standard semi tractor truck. The present chassis isconstructed and arranged so that it meets standard Department ofTransportation height and weight regulations for towed semi-typetrailers, and does not require special Oversize or Overweight permits.

Included on the present tamper apparatus chassis is a retractablepowered rail wheel assembly that features an independently pivoting railaxle assembly pivoting about an axis extending parallel to thelongitudinal axis of the respective railroad track. An axle subframe orhousing included in the rail axle assembly is selectively retractablevertically relative to the main tamper machine chassis. The pivotingaction occurs about a pivot shaft that is mounted to the subframe withspherical bearings for accommodating irregularities in the terrain. Atleast one spring-loaded latch holds the subframe in position relative tothe chassis once the rail wheels are extended to the operationalposition, in which the rail wheels are in contact with the track. Thesubframe is provided with its own power source for moving the tamperunit along the railroad track. When the tamping operation is completedand the tamper apparatus is converted for highway travel, the subframeis extended past the operational position, the at least one latch isretracted, and the subframe is retracted to a travel position using amain cylinder.

Further, due to the tamper apparatus's reduced width, length, andweight, and the turntable unit, no special crane is necessary forplacing the tamper apparatus on the track for operation. A semi-trucktractor conveniently hauls the tamper apparatus and delivers it to adestination, such as a railroad crossing. In use, the tamper apparatusis lowered and released on the railroad track so that wheels of theturntable unit are engaged on the rails. At this point, the remainder ofthe tamper apparatus is held suspended above the track and is locatedalong an axis transverse to the rails. A user manually rotates thetamper apparatus supported by the turntable assembly for subsequentoperation along the rails.

Prior to lowering the tamper apparatus into engagement with the rails,the present retractable powered rail wheel assembly is lowered relativeto the main tamper apparatus frame, to an operational position.Specialized latches are triggered once the assembly is in the lowered,operational position, to prevent retraction of the assembly relative tothe tamper apparatus frame.

Accordingly, transitioning of the present apparatus from traveling onthe road to traveling and working on the railroad track is easilyaccomplished, and is performed without resorting to additional heavyequipment or special governmental authorization. Upon completion of thetamping operation, once the tamper apparatus is readied for highwaytransport, after lifting the tamper apparatus frame from the rails, thepresent powered rail wheel assembly is slightly lowered or extendedfurther relative to the main frame by designated hydraulic cylinders.This action moves the axle frame below the reach of the latches, whichare then retracted. In this manner, the latches are released, permittingthe retraction of the powered wheel assembly relative to the main tamperframe, for highway travel.

In operation, the chassis is transitioned from highway movement to awork mode using the turntable as described above. Once the chassis isaligned with the track, the tamper apparatus moves along the track,collecting track alignment data. Once a section of track is discoveredthat requires alignment, the apparatus moves back over the misalignedrail, and a process known as indexing is begun, where the ballastsupporting each misaligned tie is subject to tamping. Once the chassisis in position, the chassis brakes are set, and the biasing clamps pressrail wheels of the turntable against an inner surface of a referencerail on one side of the machine On the opposite side, the respectivebiasing clamp is pressurized to exert pressure against the correspondinginner surface of the rail. Hydraulically controlled hook members aremanipulated to grasp and lift the corresponding rail requiring alignmentto a desired position. Next, the tamper unit is energized for movingballast to support the respective tie so that the rail maintains thedesired position held by the hook member.

A tamper machine pivoting rail wheel assembly is provided with a railwheel assembly that is pivotable relative to a chassis about a shaftextending generally parallel to the rails.

A pivoting rail wheel assembly is provided for a tamper machineincluding powered pivoting latches for retaining the wheel assembly inan extended, rail travel position.

A pivoting, extendable rail wheel assembly is provided for a tampermachine, having latches for holding the assembly relative to a chassisin an operational position, and such that extension of the assembly pastan operational position allows disengagement of the latches forretraction to a highway travel position.

More specifically, a rail tamper apparatus is provided, including achassis configured for being hitched to a semi-tractor trailer for roadtravel, and also configured for travel on rails of a railroad track, atleast one ballast tamping unit mounted to the chassis, a turntable unitmounted to the chassis, and a pivoting axle assembly mounted to thechassis that is retractable relative to the chassis in a road travelposition for highway travel, and is extendable from the chassis into atrack travel position for operation on the rails, and including a railwheel drive motor being extendable with the axle assembly.

In another embodiment, a pivoting rail wheel assembly is provided foruse with a railway maintenance vehicle having a chassis. The assemblyincludes a housing configured for being vertically reciprocable relativeto the chassis, a pair of rail wheels mounted to the housing, a drivemotor associated with the housing and configured for powering at leastone of the rail wheels, a pivot shaft associated with the housing andslidably connecting the housing to the chassis, the housing beingpivotable about the shaft, and at least one powered latch connected tothe chassis and constructed and arranged for maintaining the assembly ina track travel position relative to the chassis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the present tamper apparatus shown in a railtravel mode;

FIG. 2 is a fragmentary side view of the tamper apparatus of FIG. 1connected to a semi-truck in a travel mode;

FIG. 3 is an enlarged fragmentary side elevation of the present pivotingaxle subframe shown in a travel mode as seen in FIG. 2;

FIG. 4 is a fragmentary side elevation of the subframe of FIG. 3 shownin the operational or work mode for movement along the track whentamping is performed;

FIG. 5 is a fragmentary side elevation of the subframe of FIG. 3 shownpartially extended from the chassis past an operational position;

FIG. 6 is a fragmentary side elevation of the subframe of FIG. 3 shownas the subframe is about to be retracted, such that the main cylinderhas extended the subframe past the work mode position and the latchesare released, permitting retraction;

FIG. 7 is a front elevation of the present subframe taken along the line7-7 of FIG. 1 and in the direction indicated generally and in theretracted position; and

FIG. 8 is a front elevation of the subframe of FIG. 7 shown in the workmode position.

DETAILED DESCRIPTION

Referring now to FIGS. 1 and 2, a tamper apparatus or machine, generallydesignated 10, is shown on a portion of a semi-truck, generallydesignated 12. As is well known in the art, the tamper apparatus 10 isdesigned to be self-propelled or towed as a separate unit alone or aspart of a railway maintenance gang along a railroad track. One aspect ofthe present tamper apparatus 10 is that the tamper apparatus can beconveniently and directly towed by the semi-truck tractor 12 through theconnection with a hitch assembly 14 along the highway on road wheels 15to a destination site without requiring shipment on the railroad trackor on an oversize highway trailer.

For maintenance activities on the track, the tamper apparatus 10 isself-propelled and powered by an engine 16, a battery 18, and a fueltank 20. As is known in the art, the engine 16 is mainly used forpowering a hydraulic system, generally including at least one pump,several hydraulic motors and several hydraulic cylinders. It ispreferred that a self-contained electrical power source, such as thebattery 18, is installed on the tamper apparatus 10, but it is alsocontemplated that the power source can be obtained from another unit ofthe railway maintenance gang. Thus, the engine 16 indirectly providespower to at least one of a pair of front-axle wheels 22 and a pair ofrear-axle wheels 24, both sets of which being railway wheels foroperation along the track, allowing the tamper apparatus 10 to propelitself to the work-sites on the railroad track. Preferably, thefront-axle wheels 22 are equipped with a floating axle frame 26, and therear-axle wheels 24 are fixedly attached to an axle frame 28. However,it is contemplated that the fixed/floating conditions of the wheels 22,24 are reversed, depending on the application. While a two-axle tamperapparatus 10 is shown, any number of axle(s) is also contemplateddepending on the payload. A separate brake system 30 is installed on therear-axle wheels 24 to prevent the tamper apparatus 10 from unwantedmovement.

A pump (not shown), preferably hydraulic, is driven by the engine 16 toprovide power for various tools associated with the tamper apparatus 10.A hydraulic reservoir or tank 32 provides the fluid transmitted by thepump. For example, a ballast tamping unit 34, and a projector buggy 36are attached to a chassis or main frame 38 of the tamper apparatus 10.It is contemplated that the engine 16, the battery 18, and the fuel tank20 are also attached to the chassis 38 at desired locations. Duringrailroad track maintenance, under the direction of an operator in a cab40 mounted to the chassis 38, preferably in closer proximity to the rearwheels 24 than to the front wheels 22, the ballast tamping unit 34performs packing of the ballast 42 under railroad ties 44 forlongitudinally and transversely correcting the alignment of a pair ofrails 46 of the railroad track (best seen in FIG. 2). During thetransportation of the tamper apparatus 10 on the highway, the projectorbuggy 36 is stored on the chassis in a retracted position as describedin co-pending, commonly assigned U.S. patent application Ser. No. ______entitled RAILWAY REFERENCE MACHINE HAVING A COLLAPSIBLE PROJECTOR(Docket no. 1425.114260) incorporated by reference. Once the tampingoperation begins, the buggy lift assembly 36 is extended for providing abeam projection point for aligning the rail as is well known in the art.

A turntable unit 48, is rotatably attached at substantially a center ofmass ‘CM’ of the tamper apparatus 10, for enabling manual horizontalrotation of the tamper apparatus 360 degrees relative to a plane definedby the chassis 38. Another aspect of the present tamper apparatus 10 isthat orienting and positioning of the apparatus is easily achieved bymanually rotating the turntable unit 48 when the apparatus is lowered onthe rails 40. The turntable unit 48 is described in greater detail inco-pending, commonly assigned U.S. patent application Ser. No. ______entitled ROADWORTHY RAILROAD BALLAST TAMPER APPARATUS (Docket no.1425.114261), which is incorporated by reference. A feature of thepresent tamper machine 10 is that the projector buggy 36, the tamperunit 34, the operator cab 40 and the turntable unit 48 unit are allmounted to the chassis 38 such that the machine 10 is directly towableon the road by the semi truck tractor 12 without requiring a trailer orspecial use/oversize permits. The machine 10 has a width of less than orequal to 96 inches, a length of less than or equal to 104 feet and aweight of less than 80,000 pounds.

Referring now to FIGS. 3-6, the present retractable powered rail wheelassembly or pivoting axle assembly is generally designated 50, andincludes a housing 52 which reciprocates vertically relative to thechassis 38 under the power of a pair of lift cylinders 54, connected atone end to the chassis 38 and at another to the housing 52. The railwheel assembly reciprocates between a road travel position (FIG. 3) andan extended or track travel position (FIG. 4). Included in the framechassis 38 is a pair of vertical slots or tracks 56 which guide themovement of the housing 52, through engagement of ends 58 of a mainpivot shaft 60. The shaft 60 slidably connects the housing 52 to thechassis. More specifically, the shaft ends 58 are supported in sphericalbearings 62 which are enclosed in guide bosses 64 that are slidablyengaged in the slot 56. The shaft 60 is held in place in the slots 56 byendcaps 66 which also enclose the spherical bearings 62. Due to theweight of the tamper machine 10, the spherical bearings 62 permitflexing of the shaft 60 due to the load of the machine.

Thus, it will be seen that the housing 52 pivots about an axis definedby the shaft 60 which extends parallel to the rails 46. This pivotingaction facilitates the movement of the tamper assembly 10 on the rails46, especially about curves.

Included on the housing 52 is an axle drive motor 68, preferably ahydraulic motor powered by the pump 32 on the tamper machine 10. Themotor 68 moves with the housing 52, and powers the front axle wheels 22,which are mounted to the housing, using a transmission linkage of thetype well known in the rail maintenance art. Thus, when traveling uponthe rails 46, motive power for the tamper machine 10 is provided by themotor 68 driving the wheels 22. Also mounted on the housing 52 is abrake assembly 70 under control of the operator in the cab 40 forselectively exerting braking force on the wheels 22 through brake pads72.

An important feature of the wheel assembly 50 is that the housing 52 isheld in a locked extended position relative to the chassis 38 duringoperation of the tamper machine 10 on the rail 46 by at least one andpreferably a pair of latches, generally designated 74. The latches 74each engage a corresponding endcap 66 and also extend partially into theslot 56 for holding the housing 52 in the extended position relative tothe chassis 38.

Referring now to FIGS. 3-6, each latch 74 includes a pivoting latch arm76 pivotably mounted to a pivot boss 78 on the chassis 38 that extendstransversely to the longitudinal axis of the rails 46. A dogleg end 80of the latch arm 76 is connected to one end 82 of a fluid power latchcylinder 84, with an opposite end 86 of the cylinder being pivotallyattached to the chassis 38. While the cylinder 84 is shown as a springreturn hydraulic cylinder, other fluid power devices are contemplated,including but not limited to dual acting hydraulic cylinders.

Opposite the dogleg end 80, the latch arm 76 has a latch end 88constructed and arranged for engaging the endcap 66 and also at leastpartially inserted into the vertical slot 56. As such, the end 88 has afootplate 90 oriented at an angle ∂ to an axis of the latch arm 76 sothat when the latch arm is extended, there is a parallel, face-to-faceengagement between the footplate and an upper surface of the endcap 66(FIG. 4). A guide surface 92 (FIG. 6) on the latch arm 76 is angled tobe oriented parallel to corresponding surfaces 94 of the chassis 38adjacent the slot 56. A portion 96 of the latch end 88 actuallyslidingly engages the slot 56.

During the process of converting the tamper machine 10 from road travelto rail travel, as the lift cylinders 54 lower the housing 52 from thetravel position of FIG. 3 towards the rails 46, the guide surface 92 oneach latch arm 76 slidingly follows the surface 94. As seen in FIG. 4,once the housing 52 reaches the rail travel position, the cylinders 54are held in position, and the footplate 90 engages the endcap 66,preventing any upward movement of the housing 52 relative to thechassis. Due to the geometry of the latch arm 76, by pressurizing apiston 97 of the rod end 82 of the piston of the cylinder 84 (shownaccomplished by a coil spring 97 a, and the mechanical advantage of thechassis 38 over the latch arm, relatively little force is needed to holdthe latch arm in position. Also, it will be seen that the portion 96 ofthe latch arm end 88 is engaged in the vertical slot 56.

Referring now to FIGS. 5 and 6, when it is desired to convert the tampermachine 10 from the extended or track travel position back to the roadtravel position for highway travel, the latches 74 are released byextending the lift cylinders 54 further past the track travel position,thus distancing the endcaps 66 out of engagement with the footplates 90.Next, the latch cylinders 84 are energized for rotating the latch arms76 about the pivot bosses 78 as seen in FIG. 6 to a retracted positionso that the latch arms do not inhibit retraction of the housing 52relative to, and closer towards the chassis 38. Once the latch arms 76are free of engagement with the chassis 38, the lift cylinders 54retract the housing 52 and the latches 74 back to the road travelposition of FIG. 3.

Referring now to FIGS. 7 and 8, another important feature of the wheelassembly 50 is that the lift cylinders 54 are located outboard of thefront rail wheels 22. In addition, bearings 98 for the rail wheels 22are located inboard of the wheels. This mounting arrangement reduces theoverall width of the assembly 50 and also of the tamper machine 10, tofacilitate the machine's ability to comply with roadworthiness asrequired by US transportation regulations. A derail bar 100 (FIGS. 3-6)on the housing 52 contacts the rail 46 in the event the wheels 22 becomedisengaged from the rail. Also seen in FIGS. 7 and 8 is a pulley 102used in a preferred chain drive transmission used to transmit power fromthe motor 68 to the wheels 22 through engagement with a correspondingaxle pulley 104.

While a particular embodiment of the present pivoting axle assembly fora railroad ballast tamper apparatus has been described herein, it willbe appreciated by those skilled in the art that changes andmodifications may be made thereto without departing from the presentdisclosure in its broader aspects.

What is claimed:
 1. A rail tamper apparatus, comprising: a chassisconfigured for being hitched to a semi-tractor trailer for road travel,and also configured for travel on rails of a railroad track; at leastone ballast tamping unit mounted to said chassis; a turntable unitmounted to said chassis; and a pivoting axle assembly mounted to saidchassis that is retractable relative to said chassis in a road travelposition for highway travel, and is extendable from the chassis into atrack travel position for operation on the rails, and including a railwheel drive motor being extendable with said axle assembly.
 2. Theapparatus of claim 1, wherein said apparatus has a weight of less than80,000 pounds and a width of less than or equal to 96 inches.
 3. Theapparatus of claim 1, wherein said pivoting rail wheel assembly isprovided with a pivot shaft extending generally parallel to the rails,and said assembly is pivotable relative to said chassis about saidshaft.
 4. The apparatus of claim 1, wherein said pivoting rail wheelassembly is provided with powered latches connected to said chassis andconstructed and arranged for maintaining said assembly in said tracktravel position relative to said chassis.
 5. The apparatus of claim 4,wherein said latches are constructed and arranged for rotatablyoperating between an extended, rail travel position, and a retractedposition.
 6. The apparatus of claim 5, wherein said latches include alatch arm having a latch end configured for engaging a slot in saidchassis.
 7. The apparatus of claim 5, wherein said pivoting rail wheelassembly is provided with a main shaft with endcaps, and said latchesare configured for engaging said endcaps in said rail travel position.8. The apparatus of claim 5, further including at least one liftcylinder connected to said chassis and to said pivoting rail wheelassembly for reciprocally moving said assembly vertically relative tosaid chassis, said at least one lift cylinders being constructed andarranged such that extension of the assembly by said at least onecylinder past an operational position allows for disengagement of thelatches for subsequent retraction of said assembly to a highway travelposition.
 9. The apparatus of claim 8, further including a pair of saidlift cylinders, said lift cylinders being mounted to said rail wheelassembly outboard of a pair of rail wheels mounted to said assembly. 10.The apparatus of claim 9, further including bearings for said railwheels, said bearings being located inboard of said wheels.
 11. Apivoting rail wheel assembly for use with a railway maintenance vehiclehaving a chassis, said assembly comprising: a housing configured forbeing vertically reciprocable relative to said chassis; a pair of railwheels mounted to said housing; a drive motor associated with saidhousing and configured for powering at least one of said rail wheels; apivot shaft associated with said housing and slidably connecting saidhousing to said chassis, said housing being pivotable about said shaft;at least one powered latch connected to said chassis and constructed andarranged for maintaining said assembly in a track travel positionrelative to said chassis.
 12. The assembly of claim 11, wherein saidlatches are provided with fluid power cylinders and are constructed andarranged for rotatably operating relative to said chassis between anextended, rail travel position, and a retracted position.
 13. Theapparatus of claim 12, wherein said latches include a latch arm having alatch end configured for engaging a slot in said chassis, and said mainshaft is provided with endcaps, said latches are configured for engagingsaid endcaps in said rail travel position.
 14. The assembly of claim 12,wherein said latches are constructed and arranged, so that when in saidretracted position, said housing is movable vertically towards saidchassis.
 15. The assembly of claim 11, further including at least onederail bar disposed on said housing.
 16. The assembly of claim 11,further including a brake assembly mounted on said housing for exertingbraking force on said rail wheels.